AW: monitor hotplug resolution switch

[Johann Obermayr]

Hello,

> -----Ursprüngliche Nachricht-----
> Von: xorg [mailto:xorg-bounces at lists.x.org] Im Auftrag von Felix Miata
> Gesendet: Mittwoch, 13. Dezember 2017 11:31
> An: xorg at lists.x.org
> Betreff: Re: monitor hotplug resolution switch
> 
> Johann Obermayr composed on 2017-12-13 08:36 (UTC:
> 
> >> Johann Obermayr composed:
> 
> >>> i have a x86 machine with i915 graphics.
> 
> >>> With connected display (1920x1080) all is ok.
> 
> >>> But if I disconnect the monitor, the resolution switch to 320x200.
> 
> >>> How can I disable this ?
> 
> >>> I will always have the same resolution (1920x1080)
> 
> >>> How can I do this ?
> 
> >> some more info is certainly necessary
> 
> >> what OS?
> >> what remaining monitor?
> 
> >> what do xrandr say?
> 
> > yes, sorry.
> > X86 dualcore Intel(R) Celeron(R) CPU G1820 @ 2.70GHz With On board
> > graphics i915
> 
> 'inxi -c0 -G' and/or 'lspci -nnk | grep -A4 VGA' would tell a bit more.

00:02.0 VGA compatible controller [0300]: Intel Corporation Haswell Integrated Graphics Controller [8086:0402] (rev 06)
        Subsystem: Intel Corporation Haswell Integrated Graphics Controller [8086:0402]
        Kernel driver in use: i915

> 
> > Older Yocto build with Kernel 3.10.0
> 
> That kernel version is older than your G1820 CPU.
> 
> > X.Org X Server 1.14.0
> > Release Date: 2013-03-05
> > [1274713.521] X Protocol Version 11, Revision 0 [1274713.521] Build
> > Operating System: Linux 3.2.0-126-generic-pae i686 [1274713.521]
> > Current Operating System: Linux sigmatek-x86-mp 3.10.0 #48 SMP
> PREEMPT Wed Dec 6 18:30:54 CET 2017 i686
> > [1274713.521] Current version of pixman: 0.29.2
> 
> Why did you omit the "Kernel command line:" line? What's on it might
> explain why falling back to 320x200, if the age of your hardware being newer
> than your software does not.
> 
> > And using xf86-video-intel-2.21.3.tar.bz2
> 
> That predates the release of your G1820 (Haswell) CPU by nearly a year.

Now i have compile version 2.99.917
This support virtual outputs. (with sna enabled)

Now I will make some test with this virtual outputs.

> 
> > xorg.conf
> ...
> > Section "Screen"
> > 	Identifier "Screen0"
> > 	Monitor    "Monitor0"
> > 	DefaultDepth 16
> > 	SubSection "Display"
> > 		Viewport   0 0
> > 		Depth     16
> > 	EndSubSection
> > EndSection
> 
> > Yes we use 16 bit color depth.
> 
> That's not as well tested as the higher depths, and may cause inexplicable
> trouble.

I think intel will wrap this.
Because if I ask framebuffer, it tell me that he has 32bit color.
But only x-server will work with 16 bit.

> 
> > root at sigmatek-x86-mp:~# xrandr
> > Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
> > VGA1 disconnected
> > DP1 disconnected
> > HDMI1 disconnected
> > DP2 disconnected
> > HDMI2 disconnected
> > DP3 connected
> >    1920x1080      60.0 +
> > HDMI3 disconnected
> 
> > But after disconnect the monitor, the driver will change resolution to
> 320x200.
> > But we will, that driver does not change the resolution. Or we can define
> the default resolution.
> 
> Section "Monitor"
> ...
> 	Option		"PreferredMode"	"1920x1080"
> ...
> EndSection
> 
> PreferredMode option should define resolution preferred, if the hardware is
> supported.
> --
> "Wisdom is supreme; therefore get wisdom. Whatever else you get, get
> wisdom." Proverbs 4:7 (New Living Translation)
> 
>  Team OS/2 ** Reg. Linux User #211409 ** a11y rocks!
> 
> Felix Miata  ***  http://fm.no-ip.com/
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